1. Statement of the Technical Field
The present invention relates to processing a dynamic markup language document specified computer program and more particularly to an accessible slider control defined within a dynamic markup language specified computer program.
2. Description of the Related Art
Prior to the popularization of the Internet and the subsequent implementation of the World Wide Web (“the Web”), software publishers typically distributed computer applications via storage media such as a computer diskette or compact disc. Initially, such stand-alone computer applications included underlying program logic, data storage and, optionally, a user interface. Recently, given the popularization of the Internet and the Web, it is no longer reasonable to presume that computer applications are distributed exclusively via disk medium. Rather, in many cases, conventional computer programs are distributed electronically via the Internet. More importantly, however, in many cases computer applications are no longer distributed as stand-alone executable programs. Rather, many computer applications are distributed as markup language specified, browser based applications which can include a collection of hypermedia documents such as Web pages which can be viewed in hypermedia content browsers such as Web browsers.
In the case of a markup language specified computer program, users can interact with the underlying program logic not through a traditional GUI, but through a GUI provided by GUI elements embedded in a hypermedia document displayed in a content browser. Specifically, conventional markup can specify a user interface and corresponding logic which can be processed and rendered through use of a content browser. Content browsers, in turn, can process display attributes embedded in markup to properly format content also contained within the markup. Notable variants of the content browser include the venerable Web browser, as well as the more recent extensible markup language (XML) browser. Regardless of the type of browser, all conventional markup processors are preconfigured to parse and interpret attribute tags embedded in markup.
Markup language defined applications often have the need to present a user interface control in which a bounded range value must be specified. Slider controls which generally are well-known in the art, often are applied to control the specification of a bounded range in a GUI. In the prototypical slider control, a graphical control point can slide along a “track” that has both starting and ending points which correspond to the bounds of a valid entry range. Accordingly, given the clear importance of the slider control, though static markup languages do not provide a built-in mechanism for a slider control, dynamic forms of markup languages have been able to emulate the slider control.
Concurrently with the development of markup language defined applications, for more than ten years, computer scientists and engineers have addressed the accessibility of the computer program user interface—particularly for the benefit of those end users unable to interact with a computer program utilizing conventional means such as a mouse or keyboard. Presently, several assistive technologies have been widely distributed, usually in concert with the distribution of an operating system, to provide one or more alternative user interface mechanisms for the purpose of enhanced accessibility. Examples of assistive technologies include an audio user interface such as a screen reader.
Assistive technologies have proven to be highly successful among visually challenged computing end users. Yet, assistive technologies have not yet adapted to the underlying changes in respect to the modem form of the computer program. Specifically, whereas in a conventionally distributed computer program, assistive technologies like the screen reader can be easily enabled, markup language specified computer programs have not yet enjoyed the comprehensive integration of assistive technologies. In particular, dynamic implementations of markup languages and scripting aspects of markup languages, such as the popular dynamic hypertext markup language (DHTML) cannot always support important aspects of assistive technologies such as precise user interface element focus establishment.
In fact, it is well known that DHTML specified applications defining certain, complex user interface widgets cannot support accessible tabbing across constituent elements. Consequently, heretofore the specification of a slider control in a dynamic markup language cannot also enjoy the accessibility provided by assistive technologies. Accordingly, applications developers often must choose between providing a technically simplified albeit accessible markup language specified application, and providing a technologically advanced DHTML specified application which lacks desired accessibility features.